Furnace



R. WALKER Nov. 11, 1930.

FURNACE Filed NOV. 14, 1928 lNvElvroR ROBERT WALKER ATTORNEYS Patented Nov. 11 1930 UNITED STATES ROBERT WALKER, or vANooUvn BRITISH COLUMBIA, CANADA FURNACE Application filed November 14, 1928. Serial No; 319,375.

My invention relates to improvements in furnaces which are particularly adaptedfor use in consuming sawmill refuse, in the gen eration of steam. The objects of the invention are to provide means for promoting complete combustion of the fuel before it passes out from the combustion chamber, so that sawdust and other solids are not deposited upon the boiler surfaces or emitted from the smoke stack.

The invention consists essentially of a primary and a secondary combustion chamber in which the heated solids which rise from the fire are deflected downwards and caused to re-enter the normal stream of heated gases given off from the fire, as will be more fully described in the following specification, and shown in the accompanying drawings, in which V Fig. 1 is a longitudinal sectional view of the invention.

Fig. 2 is a transverse sectional view taken on the line 22 of Figure 1.

Fig. '3 is a plan view taken on the line 33 of Figure 1.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numeral 1 indicates generally the primary combustion chamber having a floor 2 39 and side walls 3 which are bridged across by an arch 4 having a feed opening 5 adjacent 7 its forward end. The numeral 6 indicates a front wall having a suitable air inlet opening and damper 7, one or more clean out doors 8 r and a feed or inspection door 9.

The numeral 10 indicates an air inlet trunk having side walls 11, and a top wall 12 and is provided adjacent its rear end with a plural- 9 ity of air vents 13. Extending across from one side wall 3 to the other, is a plurality of grate bars 14: arranged in stepped formation to form an inclined grate 15 extending clownwards and forward from the front wall 6 somewhat below the feed door 9. A bridge 16 extends transversely of the chamber which is provided with a duct or cavity 17 extending preferably to the outside of the side walls 3 and fitted with suitable air inlet dampers 18.

The rear face of the bridge is provided with a plurality of air vents 19, the purpose of which will hereinafter appear.

The numeral 20 indicates generally a secondary combustion chamber which is of greater height than the primary combustion chamber 1, and is covered with a similar arched .roof 21', and is separated from the arch 4 of the primary chamber by a fire arch 22.- The fire arch 22 is built of a suitable'refractory material and is provided with an arcuate cavity 23 which is open to the chamber land is provided with bottom vents 24 extending outwards to the soffit of the arch 22. The rear end of the secondary chamber 20 is provided with a fire arch 25 which is similar to the arch 22, except that it is sprung from a higher position and is provided with a similar arcuate cavity 23 and vents 2 1. Directly below the fire arch 25 is asecond bridge wall numbered 26 behind which, and the arch, a tubular boil- 7 er 27 is built in and provided with a suitable smoke stack, not shown. I A g V Immediately to the'rear of thebridge 16 and below the fire arch 22 is a perforated grate 28, which is preferably formed as a brick arch. This grate extends between the side walls 3 of the secondary combustion chamber 20 and is provided underneathwith an air inlet duct 29 havingsuitable doors 30 at one or both ends in which ventilating slides 0 .81 are provided. The rear side of theperforat-ed grate 28 is enclosed with a low retaining wall or'bridge 32 between which and the bridge 26 a dust receiving space 33- is formed having one or more clean out doors 34. r

1 Having thusdescribedfl the several parts of my invention I will now briefly explain its function. y I Y Fuel such as slabs, sawdust and other refuse is normally fed continuously from a conveyor into the primarycombustion chamber 1 through the feed opening 5, falling onto the inclined grate 15, where some of it is consumed and some falls in a burning state I to the floor2 which combustion is substantially completed by the introduction'of air thereto which has entered the trunk 10 and has been distributed over the horizontal fire area through the vents 13-. Some of the lighter particles offuel are carried upwards in the hot gases emanating from the fire, and flow into the cavity 23 of the fire arch 22, from whence they are allowed to fall through the stream of burned gases from the fire onto the perforated grate 28, where they are permitted to be properly consumed by the introduction of air from the underside of the said grate, which is controlled by the ventilating slides 81 and by the horizontal air blast passing thereoverifrom the vents 19 in the bridge wall 16. The gases of combustion from the two fires then intermingle and flow between the bridge 26 and the fire arch 25 to g the boiler 27 and thence to the smoke stack.

Should there be any unburned particles of fuel left in said gases when flowing through the combustion chamber 20, they will rise above the stream and be returned to it through the vents 24 of the fire arch 25.

What I claim as my invention is:

' 1. A furnace comprising a combustion chamber having a hollow raised portion extending longitudinally and centrally of the forward end of the chamber floor to providean air inlet trunk, said trunk having its side walls provided adjacent their inner ends with air vents, a hollow bridge extending transversely of the chamber floor at the inner end of the said trunk and in communication with the latter, said transverse bridge having air vents in its rear face, a perforated grate disposed against the rear face of, the

v transverse bridge and below the air' vents thereof, said grate beingco-extensive with said bridge, air inlets in the walls ofthe chamber communicating with the said trunk, bridge and perforated grate of the combustion chamber, a retaining wall at the rear side of the said grate, and a fire arch depending from the roof of the chamber in line with the said grate, said arch having means for receiving the lighter particles of fuel rising above the normal stream of burned gases and deflecting same through thestream 'onto the said grate.

2. A furnace. for consuming sawmill refuse, comprising means for maintaining a normal stream of hot gases flowing through the combustion chamber, means for receiving unoonsumed particles of fuel rising above the normal streamof gases and deflecting same downwardl through the said normal stream, a perforated grate below the said fuel-receiving and deflecting means for receiving the downwardly deflected fuel particles, fuel-retaining walls rising above opposite sides of said grate, one of said walls having an air-inlet duct directing a blast of air transversely across the grate in the direction of the normal stream of gases, and means for directing air upwardly through *the grate from the underside thereof.

Dated at Vancouver, B. (3., this 8th day of November, 1928;

ROBERT WALKER, 

